level: Moles
Questions and Answers List
level questions: Moles
| Question | Answer |
|---|---|
| What is Avogadros constant? | The amount of particles in one mole of a substance: 6.02 x 10^23 |
| Calculate the number of water molecules in 0.5mol of water. | Number of water molecules = Avogadro's constant x amount of substance in mol 0.5 x 6.02 x 10^23 = 3.02 x 10^23 |
| Calculate the mass of 0.25 moles carbon dioxide CO2=44 | Mass = rfm x amount (moles) Mass = 44 x 0.25 Mass = 11g |
| Calculate the mass of 0.25 moles carbon dioxide CO2=44 | Mass = rfm x moles Mass = 44 x 0.25 Mass = 11g |
| 25cm^3 of HCl of concentration 1mol/dm3 reacts with 20cm NaOH. Calculate concentration of NaOH. | Convert to cm3 to dm3: HCl = 25/1000 = 0.025 NaOH = 20/1000 = 0.020 amount(mol) = concentration x volume 0.025 x 1 = 0.025 concentration = amount solute(mol)/amount NaOH(mol concentration = 0.025/0.020 concentration = 1.25 |